This invention relates to the use of a separative bioreactor for treating fluids via electrodeionization (EDI) and more particularly, to the production of organic acids, amino acids, or amines by fermentation and/or enzymatic processes.
Electrodeionization, also known as electrochemical ion-exchange, is an advanced ion-exchange technology that combines the advantages of ion-exchange and electrodialysis. In an electrodeionization process, ion exchange resins are sequestered in dilute compartments to increase ionic conductivity, so that even with very dilute ionic feed (10−5N), a stable operation with higher flux and lower energy consumption than electrodialysis becomes possible. EDI technology is presently used to make deionized water for boiler feed and high purity and industrial water applications. However, there are also other uses and potential uses of such technology for processing organic streams in a variety of industries. Some of these technologies have been touched on by patent applications and/or issued patents filed on behalf of Argonne National Laboratory (ANL) such as U.S. Pat. No. 6,797,140 issued Sep. 28, 2004 and U.S. Ser. No. 10/702,798 filed Nov. 5, 2003 and U.S. Pat. No. 6,495,014 issued Dec. 17, 2003, the entire disclosures of each of these references being herein incorporated by reference.
In many fermentation and enzymatic processes, it is frequently required to maintain a high (milimolar) concentration of medium components. Common examples are mono and divalent cations and anions that provide an appropriate required ionic environment for optimum activity of microorganisms and enzymes. These mono and divalent cations and anions are identified as counterions hereinafter and the concentrations of them in the reaction medium should be maintained within a predetermined range to ensure optimum reaction conditions. During the direct capture of ionic products such as organic acids, amino acids and amines and an EDI driven separative bioreactor device, sometimes important ionic species such as counterions are separated from the fermentation broth or reaction medium. It is this loss of counterion concentration in the fermentation broth or reaction medium that is a serious problem in the art because replacement of the counterions in a flow through system would be expensive and prohibitively increase the cost of obtaining the product.